Abstract Objectives The aim of this study was to test the feasibility and usefulness of a new delayed-enhancement cardiac magnetic resonance (DE-CMR)–guided approach to ablate gaps in redo ...procedures. Background Recurrences of atrial fibrillation (AF) after pulmonary vein isolation (PVI) may be related to gaps at the ablation lines. DE-CMR allows identification of radiofrequency lesions and gaps (CMR gaps). Methods Fifteen patients undergoing repeated AF ablations were included (prior procedure was PVI in all patients and roof-line ablation in 8 patients). Pre-procedure 3-dimensional (3D) DE-CMR was performed with a respiratory-navigated (free-breathing) and electrocardiographically gated inversion-recovery gradient-echo sequence (voxel size 1.25 × 1.25 × 2.5 mm). Endocardium and epicardium were manually segmented to create a 3D reconstruction (DE-CMR model). A pixel signal intensity map was projected on the DE-CMR model and color-coded (thresholds 40 ± 5% and 60 ± 5% of maximum intensity). The DE-CMR model was imported into the navigation system to guide the ablation of CMR gaps, with the operator blinded to electrical data. Fifteen conventional procedures were used as controls to compare procedural duration, radiofrequency, and fluoroscopy times. Results Fifteen patients (56 pulmonary veins PVs; 57 ± 8 years of age; 9 with paroxysmal AF) were analyzed. In total, 67 CMR gaps were identified around PVs (mean 4.47 gaps/patient; median length 13.33 mm/gap) and 9 at roof line. All of the electrically reconnected PVs (87.5%) had CMR gaps. The site of electrical PV reconnection (assessed by circular mapping catheter) matched with a CMR gap in 79% of PVs. CMR-guided ablation led to reisolation of 95.6% of reconnected PVs (median radiofrequency time of 13.3 interquartile range: 7.5 to 21.7 min/patient) and conduction block through the roof line in all patients (1.4 interquartile range: 0.7 to 3.1 min/patient). Compared with controls, the CMR-guided approach shortened radiofrequency time (1,441 ± 915 s vs. 930 ± 662 s; p = 0.026) but not the procedural duration or fluoroscopy time. Conclusions DE-CMR can successfully guide repeated PVI procedures by accurately identifying and localizing gaps and may reduce procedural duration and radiofrequency application time.
Catheter contact force (CF) has a strong correlation with lesion formation during radiofrequency ablation. Delayed-enhancement cardiac magnetic resonance (DE-CMR) provides lesion information in ...patients with prior atrial fibrillation (AF) ablation.
The aim of this study was to determine the CF threshold to create permanent lesions detected by DE-CMR.
A total of 36 patients referred for AF ablation were included. A CF catheter was used during the ablation procedure, and DE-CMR was performed 3 months after the ablation procedure. Eighteen pulmonary vein (PV) segments were defined, and 3-dimensional (3D) reconstructions of the left atrium (LA) derived from the DE-CMR images were obtained. One observer evaluated the presence of any discontinuity of previous ablation lesions (gap) in the 3D reconstructions of the LA, and another observer (blinded to the gap findings) determined the minimum CF value in each PV segment.
The PV segments where a gap was observed had a lower maximal CF value than did the segments without gap in the 3D LA reconstructions (6.7 ± 4.4 g vs 12.2 ± 4.7 g; P < .001). In receiver operating characteristic analysis, a CF threshold of >8 g provided 73% sensitivity and 81% specificity in the prediction of a complete PV lesion (positive predictive value PPV 84%). A CF threshold of >12 g had a specificity of 94% and increased the PPV to 91% in creating a complete lesion in the LA wall (area under the curve 0.834).
A CF threshold of >12 g H5H20 predicts a complete lesion with high specificity and PPV when a dragging ablation strategy is used in AF ablation.
Perimitral flutter (PMF) is a common form of left atrial tachycardia after atrial fibrillation (AF) ablation. The mitral isthmus (MI) is the standard ablation target. However, in some cases ...bidirectional block cannot be achieved.
The purpose of this study was to describe the first experience using a transthoracic epicardial (TTE) approach to treat recurrent PMF after prior unsuccessful ablation.
This is a case series of four patients with recurrence of highly symptomatic drug-refractory PMF (all male, median age 55 years, 3/4 hypertensive, 2/4 persistent AF, median AF period 24 months). Three patients presented with PMF-related tachymyocardiopathy. TTE ablation of MI was performed after a median of two prior endocardial MI and coronary sinus ablation attempts, using an open-tip 3.5-mm irrigated catheter (40 W, 45ºC). Persistent bidirectional block was assessed by activation mapping and differential pacing and was achieved in all patients.
No PMF recurrence was observed after median follow-up of 18 months (range 15-22 months; two patients without antiarrhythmic drugs and two with previously ineffective amiodarone). Left ventricular function normalized in all three patients with tachycardiomyopathy. There were no complications related to TTE approach.
The present study is the first to report the feasibility of a TTE approach for highly symptomatic PMF refractory to endocardial and coronary sinus MI ablation.
Abstract We present a case of a magnetic resonance imaging-assisted ablation of an atrial tachycardia in a patient with previous atrial fibrillation ablation. A 3-D reconstruction of the ...delayed-enhanced cardiac magnetic resonance (CMR; CMR model) was created to identify previous ablation lesions and gaps. Multiple gaps around right-sided pulmonary veins were observed. The activation map identified a dual-loop re-entry around both right-sided pulmonary veins, confirming that the substrate identified using delayed-enhanced CMR was critical to sustain the tachycardia. Ablation at this site converted to sinus rhythm. The present case shows the usefulness of delayed-enhanced CMR substrate characterization to complement activation mapping of the tachycardia and more accurately define the anatomical circuit.
Since Haissaguerre et al first described the pathogenic role of pulmonary vein firing as a crucial mechanism triggering atrial fibrillation, catheter ablation has been recommended as a curative ...treatment. Several trials have demonstrated that ablation is an effective treatment in most patients with paroxysmal atrial fibrillation and low-grade remodelled atria. In patients with persistent AF, there is substantially less evidence, mostly based on non-randomized studies, supporting this recommendation. The available scientific evidence as well as the current approaches to treating persistent AF patients are discussed in this article. Further, we describe the main findings of the SARA trial and put them into perspective.
Up to one-third of patients who undergo cardiac resynchronization therapy do not obtain clinical benefit. A systematic approach can identify treatable causes in many nonresponding patients. We ...present a case of nonresponse to cardiac resynchronization therapy that resolved by ablation of the atrioventricular node in a patient with complete atrioventricular block. (Level of Difficulty: Advanced.)
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